The boy, who is in police custody, has not been identified, though his country of origin is known, said Hans Lippens, a police spokesman for the Västra Götaland region.

The incident happened at a home for asylum seekers younger than 18 where the boy was staying, about 6 miles (10 kilometers) from Mölndal town center, in the Gothenberg region of western Sweden. The victim, a 22-year-old woman, was alone with eight young male residents of the home, Lippens said. Only one is believed to have been directly involved, though police are questioning the seven other boys.

"This was not terrorism. We think it might have been an accident, or there was a fight," Lippens said. He added that police would release more information Tuesday, but because the youths are from different countries, they need various translators to interpret their statements.

Incidents involving asylum seekers in the Västra Götaland region are happening "more and more. We have a lot of work to do here" Lippens said, though "this is the worst case yet." He estimated the region is seeing an additional 50 asylum seekers every month, mostly from Syria and Afghanistan.

Most incidents involve the refugees "starting fights with each other" and do not involve the local Swedish population, he said.